Flat Roofs

Our Independent Surveyors can offer a wide range of survey reports; from Building Surveys (also known as Full Structural Surveys), to Homebuyers Reports, to Specific Defects Reports for issues such as roof problems, dampness issues, subsidence, and much more.

If you have a property problem we may even have written an article on it and we would refer you to the many articles we have on our free property articles page Click Here

If you have a property problem please free phone us on 0800 298 5424 and one of our friendly, expert Building Surveyors will call you back.

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Types of roof problems

Roof problems fall into two categories: 1. Repairable Roof or 2. Replacement Roof Required.
Roofs themselves fall into two categories: 1. Pitched Roof or 2. Flat Roof

(Please see our articles on common and not so common pitched roofs FIND OUT MORE).

Flat roofs

Five main types of flat roofs:


1. Asphalt roof


2. Mineral felt roof


3. Mono-ply roof


4. Metal sheet roofing

5. Inverted roof

Asphalt Roofs

In our experience Asphalt roofs are by far the best of all the flat roof materials we have come across, although they require good decking, which is something that's very often missing. Asphalt is a very solid tarmac based product that is said to offer a life of 25 years plus. To reiterate Asphalt is by far the best of all the flat roofing materials.

Asphalt roof problems

Asphalt has the occasional blister/bubble problem that will need repair and sometimes Asphalt suffers from crocodile cracking.
Crazing or crocodiling to the surface is another sign that Asphalt is deteriorating.

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Asphalt Roof

Solar paint or not?

Although we have seen many roofs without solar paint we would recommend that it be added. This is to help reflect the heat of the hottest parts of the day, particularly in the summer time, when deterioration and damage would occur to the top of the surface if the reflective coat wasn't in place. If you do have a reflective coat you need to keep this in good order, if you don't you need to ask the contractor why and if there is no good reason we recommend you add one.

We would always recommend walkways on roofs

As an aside that came to mind when we were considering the different types of roofs, we would always recommend that a walkway be placed on a roof, particularly a roof that is going to be accessed a great deal. It may sound strange if you have a residential house, but if you have a commercial property with, say, air conditioning units on top of it and a plant room, for example for lifts and water tanks, etc, then there is quite a lot (relatively speaking) of trades people visiting the roof, all of which can damage it. Therefore, we strongly recommend a walkway.

Mineral felt roofs

Often flat roofs are associated with roof problems. Over the years our Building Surveyors have seen the quality of the materials improve. We would comment that, in our experience, many flat roof problems are caused equally by poor workmanship or poor design or detailing, rather than the materials themselves. However, deterioration can occur to the felt due to sunlight, excessive ponding (water sitting on the roof), general freeze/thaw action, gradual wind and driving rain erosion, the list is almost endless. At the end of the day you need to have someone look at the roof to give you an impartial view and not someone who is just trying to get some work from you.

Our Independent Building Surveyors give you 100% impartial property advice

Free phone 0800 298 5424 today

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Mineral Felt Roof

Mono-ply roofs

A Mono-ply roof is a single sheet of material that seals the roof and makes it watertight. A Mono-ply roof is often described as being like a swimming pool lining. This is not commonly seen on residential properties, but is very common on commercial properties. We suspect this is due to price and the flexibility of its use.

Mono-ply roof problems

In our experience we have come across problems where maintenance staff walked upon the roof and damaged it. We have also come across problems where the insulation below had deteriorated and allowed ponding in the roof, which had then caused deterioration. The Jury is still out with regard to the success of this type of roof in the UK. One of the issues with it is finding trades people that know how to repair Mono-ply roofs.

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Mono-ply roof covering

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Felt roof with ponding

Metal sheet roofing

Our Independent Building Surveyors sometimes come across metal sheet roofing when conducting residential full structural surveys, for example used for garage roofs, etc. Metal sheet roofing is sometimes used on modern apartments, which seems to be fairly common. However the most frequent use of metal sheet roofing our Building Surveyors have come across is for use on commercial properties, particularly industrial units.

Problems can occur with metal sheet roofing and with asbestos cement due to fixing deterioration, or damage where the metal sheets have been cut and the metal is exposed (metal sheets are normally covered by a protective plastic layer) leading to rusting.

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Metal sheet roofing

Problems with Profile Metal Sheeting

Whilst carrying out full structural building surveys our Building Surveyors have come across problems with profile metal sheeting particularly where the sheeting has been cut and is starting to rust.

Asbestos cement sheets

On domestic properties Asbestos cement sheets are often used on extensions or pre-fabricated garage units. It was very common in the 1960's and, to some extent, in the 1970's. Asbestos was only relatively recently banned for health reasons. In the commercial market Asbestos cement sheets were used predominantly on industrial buildings for their roofs. Please see our specific article on this:


If you are thinking about carrying out any work you do need to get independent specialist advice regarding Asbestos.

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Flat roofs and handrails

Where work has been carried out on flat roofs there should be a handrail for safety to prevent people, when working or viewing the roof from falling off and also a kicker board to stop anything from being kicked off the roof. On larger and higher roofs it is recommended that all operatives are secured in and it becomes much more like a mountain climbing operation than a building operation!

Where you have large areas of flat roofing, particularly in the commercial sector where it is going to be visited, you will need to put handrails around it to give safe access to any plant, etc that needs to be maintained.

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Inverted Roof

Inverted Roofs

An inverted roof is a roof that you cannot see as it is hidden beneath paving slabs or pavers, as they are also known. An inverted roof is difficult to view also as there is normally insulation present too.

Often a problem with this type of roof is that there is rainwater sitting underneath an inverted roof.

Regular inspections are required as often vegetation can grow, which can cause deterioration to the inverted roof. This indicates that rainwater has collected for a long time allowing vegetation and plants to grow!

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Inverted Roof

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Inverted roof pavers - pen indicates where water was found underneath paver

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Vegetation growing on inverted roof

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Inverted roof pavers



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How do I repair my roof?

How do I find a good roofer?

The question How do I find a good roofer? probably has to be equivalent to the How long is a piece of string? question. First we would say you need to ensure that whoever you use has your best interest at heart rather than their best interest and that they are not simply trying to sell you the most profitable solution to them. Word of mouth is a great way of finding good builders but do be aware that often word of mouth recommendations come via someone who doesn't have any experience or expertise or working with builders.

Therefore the reasons for their word of mouth could be that the builder turned up on the day that he said he would, finished the job on the day that he said he would and charged the price he said he would, which ironically can be a good recommendation, but not if the work carried out was technically wrong or of poor quality. You should also take great care if your property is an old property as it could be a Listed Building or in a conservation area or simply need a builder that knows how to deal with older properties.

Our Surveyors can help you if your building is a Listed Building FIND OUT MORE

Don't buy a problem property buy a Survey

Equally, a newer property also has to be dealt with in an appropriate manner, so the experience the builder has is very important. We have developed a Specific Defects Report for looking at a specific problem, such as chimneys on your property. These originally developed from our Engineers Report that specifically looked at structural cracks in properties, which then moved onto us giving specific advice on dampness in properties, due to many contracts being involved in this industry simply being there to sell a product rather than to give you best advice.

Independent Property Advice

If you truly do want an independent expert opinion from a Surveyor with regard to chimneys, roof problems, roof repairs, roof materials or any other matters please contact 0800 298 5424 for an Independent Building Surveyor to give you a call back.

A call today will save you time and money

Free phone 0800 298 5424

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Access requirements

It is very, very likely that on a re-roof or a major repair scaffolding will be required. Scaffolding is not cheap and you will also have to make the decision as to whether a roof is put over the top of the scaffolding in case it rains or there is inclement weather during the course of the repair or renewal work to the roof. Please see our article on scaffolding READ MORE

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Work carried off long ladders and crawler boards

In years gone by most roofing work would be carried out off long ladders and crawler boards. This simply wasn't safe then and is certainly not safe now. A good contractor will insist upon a scaffolding to work from, even where the site is difficult, for example where there is a shop front that you have to work around, there are scaffolding solutions. In that instance using a unitary scaffold. Some people use unitary scaffolds all the time as it saves them time, but we certainly would not recommend crawler boards and a ladder.

If you would like help and advise with regard to roofs, roof problems, roof repairs, roof materials or any other matters please call 0800 298 5424 for a friendly chat. Please note we are independent surveyors.
If you have a commercial or leasehold property and would like Dilaps Help then please visit our www.DilapsHelp.com website and for Disputes go to our Disputes Help site www.DisputesHelp.com .

We hope you found the article of use and if you have any experiences that you feel should be added to this article that would benefit others, or you feel that some of the information that we have included is wrong then please do not hesitate to contact us (we are only human).

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Roof Problems and Information
Common Pitched Roofs
Not So Common Pitched Roofs